The present invention generally relates to inkjet and other types of printers and more particularly to a novel printing system having a printhead that includes a system and method for providing localized control of the internal operations of a processor of an inkjet printhead.
Inkjet printers are commonplace in the computer field. These printers are described by W. J. Lloyd and H. T. Taub in xe2x80x9cInk Jet Devices,xe2x80x9d Chapter 13 of Output Hardcopy Devices (Ed. R. C. Durbeck and S. Sherr, San Diego: Academic Press, 1988) and U.S. Pat. Nos. 4,490,728 and 4,313,684). Inkjet printers produce high quality print, are compact and portable, and print quickly and quietly because only ink strikes a printing medium, such as paper.
An inkjet printer produces a printed image by printing a pattern of individual dots at particular locations of an array defined for the printing medium. The locations are conveniently visualized as being small dots in a rectilinear array. The locations are sometimes xe2x80x9cdot locationsxe2x80x9d, xe2x80x9cdot positionsxe2x80x9d, or xe2x80x9cpixelsxe2x80x9d. Thus, the printing operation can be viewed as the filling of a pattern of dot locations with dots of ink.
Inkjet printers print dots by ejecting very small drops of ink onto the print medium and typically include a movable carriage that supports one or more print cartridges each having a printhead with ink ejecting nozzles. The carriage traverses over the surface of the print medium. An ink supply, such as an ink reservoir, supplies ink to the nozzles. The nozzles are controlled to eject drops of ink at appropriate times pursuant to command of a microcomputer or other controller. The timing of the application of the ink drops typically corresponds to the pattern of pixels of the image being printed.
In general, the small drops of ink are ejected from the nozzles through orifices or nozzles by rapidly heating a small volume of ink located in vaporization chambers with small electric heaters, such as small thin film resistors. The small thin film resistors are usually located adjacent the vaporization chambers. Heating the ink causes the ink to vaporize and be ejected from the orifices.
Specifically, for one dot of ink, a remote printhead controller, which is usually located as part of the processing electronics of the printer, activates an electrical current from an external power supply. The electrical current is passed through a selected thin film resistor of a selected vaporization chamber. The resistor is then heated for superheating a thin layer of ink located within the selected vaporization chamber, causing explosive vaporization, and consequently, a droplet of ink is ejected through an associated orifice of the printhead.
However, current inkjet printheads do not have the ability to access and process certain data and make their own analyzed and efficient decisions, such as firing and timing decisions and thermal and energy regulation, because they are typically controlled by remote devices. Therefore, what is needed is a new printing system and protocol having a distributive processor integrated in a printhead for allowing a printhead to make its own analyzed decisions. What is also needed is an internal control system for controlling the internal operations of the distributive processor for providing efficient and localized control of the printhead.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention is embodied in printing system having a distributive processor integrated in a printhead and an internal control system for controlling the internal operations of the distributive processor for providing efficient and localized control of the printhead.
Some of the internal operations include thermal, energy, firing and timing aspects of the printhead. The printhead of the present invention provides data and control capabilities that provide efficient and localized control of the internal printhead processor operations. The printing system of the present invention includes a controller, a power supply and a printhead assembly having a memory device and a distributive processor integrated with an ink driver head. The printhead assembly also includes several electronic systems for efficiently controlling the thermal, energy, firing and timing decisions pertaining to the ink driver head. In addition, the printing system provides full digital functionality and interaction between these systems.